In the 1950s, British researchers in child psychology and psychiatry began to challenge the law concerning the institutionalisation and treatment of children with severe mental illness using the concept of ‘autism’ as their guide. This paper shows how clinicians and researchers such as Elwyn James Anthony, Mildred Creak, Victor Lotter and Michael Rutter laid the foundations for current autism research in the U.K. These researchers critiqued the therapeutic nihilism then existing concerning the treatment of severely mentally-ill children and developed new institutional and intellectual networks which championed the study of children’s abnormal emotions and social awareness as a consequence of their ‘autism’. Their radical reconceptualisation of the central tenets of child development led to major reforms in health and education policy for children with mental illness and these reforms continue to influence the way in which children’s emotions are framed and understood in both social and scientific contexts. This paper shows how British researchers of the 1950s and 1960s worked simultaneously as both government advisors and scientists in order to develop a new context in which to understand psychological development in children and its abnormalities.